Numerical simulations for microvascular shape memory polymer composites

Abstract

Microvascular shape memory polymer (SMP) composites are a new class of active composites consisting of an embedded microvascular network in a SMP matrix. The microvascular network can be used to deliver thermal, chemical, electrical, and magnetic stimulation to the SMP matrix thus integrating the activation/deactivation mechanism and opening up a new functional space for active polymers. Here, we focus on thermomechanical coupling triggered through fluid transport within the polymer. A modified thermo-viscoelastic model is used to simulate the response of microvascular SMP composites. The model is developed within a finite deformation continuum mechanics framework and captures the free recovery response of the SMP composite. The present model includes two glass transition temperatures to describe the structural relaxation time and the stress relaxation time, respectively. The model results are calibrated with experimental data from the literature. Lined and unlined microvascular composites fabricated with a varying number of channels and thermal profiles were recorded by infrared camera. Using a range of thermal inputs, we calculate the corresponding free recovery response of microvascular SMP composites. We show that the response can be optimized by tailoring a number of controllable parameters including channel spacing, inlet temperature, fluid flow rate, and the heating/cooling protocol.